JP2004129847A - Microwave surgical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microwave surgical device not affecting an MR image of an MRI device. <P>SOLUTION: A noise filter 3 is disposed between a microwave oscillator 57 and an input end of a high-frequency coaxial cable 4, thereby eliminating noise of frequency band of an MR signal of the MRI device 6 generated by magnetron of the microwave oscillator 57 when a microwave is radiated from a microwave surgical electrode 5, so that even in the case of operation by using the microwave surgical device while the MR image is displayed by the MRI device 6, a clear MR image can be displayed from the MRI device 6. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a microwave surgical apparatus for performing operations such as coagulation, hemostasis, and resection by irradiating a living tissue with microwaves.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a microwave surgical apparatus has been known together with an electric surgical apparatus (electric scalpel), a laser surgical apparatus (laser scalpel), and the like.
A microwave surgical device is a surgical device that performs coagulation, hemostasis, excision, and the like by irradiating microwaves into a living tissue and using dielectric heat generated in the tissue, such as a liver containing a large amount of blood. It is considered to be suitable for the operation of the parenchymal organ.
[0003]
By the way, when performing an operation or treatment of a living tissue using the above-described microwave operation apparatus, it is desirable to perform the operation or observation while observing the state of the operation / treatment site.
In order to observe an operation / treatment site while performing an operation / treatment using a microwave operation apparatus, it is conceivable to combine a microwave operation apparatus with a nuclear magnetic resonance imaging (MRI: Magnetic Resonance Imaging) apparatus.
[0004]
However, a nuclear magnetic resonance imaging apparatus (hereinafter, referred to as an “MRI apparatus”) applies a high-frequency magnetic field (RF magnetic field) in a state where a human body is placed in a static magnetic field to excite spin nuclei in the human body. This device detects an MR signal of a predetermined frequency generated while the excited nucleus returns to its original state, and displays a tomographic image of a human body.
For this reason, in general, a strong static magnetic field generated from a magnet does not go out of a predetermined area to the outside, and in order to efficiently receive an extremely small amount of RF signal emitted from the human body, it is placed inside a shield room where an electromagnetic shield is applied. It is necessary to provide a structure such that a small amount of MR signal is not affected by noise or the like by installation.
[0005]
Therefore, in the conventional microwave surgical apparatus, a microwave oscillator is provided outside the MR examination room, and the microwave oscillator is connected to a microwave application used in the MR examination room by a microwave relay cable. In addition, by installing a coaxial filter in the middle of the microwave relay cable connecting the microwave oscillator and the microwave application, the noise output from the magnetron is reduced before entering the MRI observation space in the MR examination room. There is also proposed a method of cutting the image (Patent Document 1).
[0006]
[Patent Document 1] Japanese Patent Application Laid-Open No. H11-267133 (pages 12 to 13, FIG. 31 to FIG. 37)
[0007]
[Problems to be solved by the invention]
However, for example, when performing an operation using the microwave operation apparatus described in Patent Document 1 as described above, usually, other treatment equipment or a living body monitoring apparatus is used in combination. If an abnormality occurs in the ground circuit of any device including any one of the devices for some reason, an operator or a patient may cause an electric shock (an electric shock or an electric shock) due to a leakage current, and may be in a dangerous state.
[0008]
In addition, in a microwave surgical apparatus, an affected area such as a tumor is irradiated with microwaves using a microwave surgical electrode to perform an operation such as coagulation of a lesion, hemostasis, and excision. It is desirable to perform the state while confirming the state with an MR image (tomographic image).
[0009]
However, when using a microwave surgical apparatus and an MRI apparatus at the same time, if an instrument that affects the magnetic field is used as the surgical instrument of the microwave surgical apparatus, the distortion of the local magnetic field generated by the surgical instrument may be reduced. It becomes a problem.
For this reason, surgical electrodes and the like are made of a non-magnetic material. However, in surgery under MR imaging, it is essential to be able to confirm a clearer image in real time. The use of magnetic field MRI devices is desired.
As a result, with the use of an MRI-compatible surgical instrument, the disturbance of the MR image obtained by the MRI apparatus still poses a problem.
[0010]
In addition, depending on the type of the MRI apparatus, there is an MRI apparatus that can secure a region that is not affected by a magnetic field even in a narrow operating room due to a leakage magnetic field. In this case, it is possible to use a normal surgical instrument. However, in that case, the operation is performed on a bed directly facing the outside of the gantry of the MRI apparatus, and the photographing is based on equipment and a system that enables quick work of quickly moving the bed into the gantry, and real time. It was difficult to confirm the MR image.
[0011]
In view of the above, the present invention has been made in view of the above points, and can display a high-resolution image in real time without affecting an MR image even when used simultaneously with an MRI apparatus. It is an object of the present invention to provide a safe microwave operation apparatus even when the apparatus is used in combination.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the microwave surgical apparatus according to the present invention can be used in a state where a tomographic image is being captured by a nuclear magnetic resonance imaging apparatus.
A microwave oscillating means, which is constituted by a magnetron, is provided with an electrical insulator that cuts off direct current in an output circuit that oscillates and outputs a microwave signal of a predetermined frequency, and irradiates the microwave signal to a lesion tissue site A surgical electrode configured to be capable of being provided between the microwave oscillating means and the surgical electrode, and a continuity noise included in a microwave signal output from the microwave oscillating means and a tomographic imaging frequency. Noise filter means for guiding only the resonating noise component to the external ground for removal.
[0013]
In addition, the noise filter means removes a noise component that affects a tomographic image captured by the nuclear magnetic resonance imaging apparatus, thereby enabling real-time display of a temperature distribution of a lesion tissue site in the nuclear magnetic resonance imaging apparatus.
The noise component to be removed by the noise filter is determined by the magnetic field strength of the nuclear magnetic resonance imaging apparatus.
[0014]
Further, the noise filter means is inserted into each of a pair of transmission paths for transmitting the microwave signal from the microwave oscillation means to the surgical electrode, and is formed so as to be able to pass at least a microwave signal of a predetermined frequency. A second band-pass circuit is inserted between the transmission path and the external ground, and is formed so as to be able to pass only a noise component having a frequency that resonates with the imaging frequency of the tomographic image, out of continuity noise generated by the magnetron. Band pass circuit.
Further, the first band-pass circuit is formed by a capacitor, and the second band-pass circuit is formed by a tuning circuit in which a capacitor and an inductor are connected in series.
[0015]
According to the present invention, a noise filter is provided between the microwave oscillating means and the surgical electrode, and the continuity noise included in the microwave signal output from the microwave oscillating means is used to resonate with the imaging frequency of the tomographic image. Only the noise component generated is guided to the external ground and removed.
Thus, even when the microwave surgical apparatus is used simultaneously with the MRI apparatus, a high-resolution image can be obtained, and thus the temperature distribution of the lesion tissue site can be displayed in real time.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a microwave surgical apparatus according to the present embodiment will be described.
The description of the present embodiment will be made in the following order.
1. Surgery system using the microwave surgery apparatus of the present embodiment
2. Configuration of microwave surgery device
2-1 External configuration of microwave surgical device
2-2 Internal configuration of microwave surgery device
2-3 Structure of Microwave Surgery Electrode
3. Background of the Invention
4. Configuration of noise filter
4-1 Structure of noise filter
4-2 Filter characteristics
[0017]
1. Surgery system using the microwave surgery apparatus of the present embodiment
First, an outline of a surgical system using a microwave surgical apparatus according to an embodiment of the present invention will be briefly described with reference to FIG.
The operation system shown in FIG. 1 includes a microwave operation apparatus 1 and an MRI apparatus 6 according to the present embodiment.
The microwave surgical apparatus 1 according to the present embodiment is generated in living tissue by converging and irradiating a 2450 MHz microwave signal generated in the surgical apparatus main body 2 from the microwave surgical electrode 5 to the affected part of the subject 7. Utilizing the generated dielectric heat, it is suitable for performing clotting, hemostasis, resection, etc. on a solid organ such as a liver containing a lot of blood.
In this case, the surgical apparatus main body 2 is connected to the high-frequency coaxial cable 4 via the noise filter 3, and the microwave operation electrode 5 is connected to the high-frequency coaxial cable 4.
[0018]
The MRI apparatus 6 is a so-called open-type MRI apparatus including an MRI apparatus main body 6a and magnet units 6b and 6b, and is an MRI apparatus main body 6a for performing main control and an MRI apparatus for applying a static magnetic field to a subject (patient) 7. The magnet parts 6b, 6b are connected by a signal line 6c. Further, the monitor 6d for displaying a tomographic image (MR image) of the subject 7 is provided.
The advantages of the MRI apparatus 6 are that there is no X-ray exposure and a tomographic image of the human body can be obtained from any angle without moving the subject's body, so that the spread of the lesion, its size, the relationship with surrounding tissues, and the temperature image And the like can be displayed on the monitor 6d.
In addition, the open type MRI apparatus 6 as shown in FIG. 1 is different from the closed type (tunnel type) MRI apparatus in that the surgeon operates between the magnet sections 6b, 6b forming the static magnetic field of the MRI apparatus. Can access the subject 7 in a static magnetic field. That is, since a space for an operator (not shown) to access the subject 7 is provided in the up-down direction, the operator is positioned in front of the space, and thus the state of the lesion displayed on the monitor 6d Various procedures such as surgery can be easily, accurately, and safely performed while visually recognizing MR images in real time.
[0019]
In the present embodiment, the MRI apparatus 6 is an open type MRI apparatus as shown in FIG. 1, and the magnet units 6b, 6b are arranged vertically, so that the surgeon accesses a subject in a static magnetic field. The vertical type (double donut type) device in which the space is provided in the vertical direction is described as an example, but this is merely an example.
For example, the MRI apparatus 6 may be a horizontal (hamburger type) apparatus in which the magnet units 6b and 6b are arranged horizontally and a space for the operator to access the subject is provided in the horizontal direction. Further, a closed type (tunnel type) MRI apparatus may be used.
[0020]
The microwave surgical apparatus 1 of the present embodiment constituting the surgical system shown in FIG. 1 is configured so as not to affect the MR image even when used simultaneously with the MRI apparatus 6. Thus, for example, by irradiating a microwave signal to an affected part such as a tumor using a microwave surgical electrode, it is possible to perform operations such as coagulation, hemostasis, and resection of a lesion while confirming in real time an MR image. It was made.
Furthermore, even when another device is used in combination, a safe configuration is provided so that the surgeon or the patient does not receive an electric shock due to the leakage current.
[0021]
2. Configuration of microwave surgery device
2-1 External configuration of microwave surgical device
Hereinafter, the configuration of the microwave surgical apparatus according to the present embodiment will be described with reference to FIGS.
First, the external configuration of the microwave surgical apparatus according to the present embodiment will be described with reference to FIGS.
FIG. 2 is a diagram showing an external configuration of the microwave surgical apparatus according to the present embodiment. FIG. 3 (a) is a front view of a surgical apparatus main body, and FIG. 3 (b) is a rear view thereof. is there.
As shown in FIG. 2, the surgical device main body 2 of the microwave surgical device 1 is small and can be arranged on the gantry 10. Further, by connecting the surgical apparatus main body 2 and the foot switch 9 (9a, 9b) with the foot cable 8, the on / off operation by the foot can be performed.
[0022]
As shown in FIG. 3A, a main operation panel section 11 is provided on the upper side, and a sub operation panel section 12 is provided on the lower side.
The main operation panel section 11 is divided into an alarm area 13, a mode area 14, a coagulation area 15, a dissociation area 16, and a memory area 17.
The alarm area 13 is provided with various alarm lamps 21 for notifying the state of the microwave surgical apparatus 1.
[0023]
The mode area 14 is an area for switching the operation mode of the microwave surgical apparatus 1. The operation mode using the foot switch 9 shown in FIG. A mode changeover switch 22 for switching to a mode (just stepping on) and a repeat number display section 23 for displaying the number of repeats are provided.
[0024]
The coagulation area 15 is an area for performing various settings of microwaves to be irradiated when performing surgery (coagulation) on the subject 7 from the microwave surgical electrode 5. For this reason, the microwave output setting, the microwave output setting switches 24 and 25 for resetting the output setting, the reset of the coagulation time, or the microwave while gradually increasing the microwave output to the output set value gradually There are provided changeover switches 26 and 27 for switching to a slow coagulation mode for irradiating light.
A coagulation confirmation lamp 28 as a display unit, an output display 29 for displaying an output value of microwaves, a coagulation time display 30 for displaying a coagulation time, and a coagulation time unit confirmation for displaying a unit (second / minute) of a coagulation time A lamp 31 is provided.
[0025]
The dissociation area 16 is an area for performing various settings for preventing biological tissue from adhering to the microwave surgery electrode 5 when the microwave surgery electrode 5 is pulled out from the living body of the subject 7. And a dissociation time display 33, a dissociation time setting switch 34, a dissociation current display 35, and a dissociation current setting switch 36.
[0026]
The memory area 17 is provided with a memory switch 37 for storing settings of coagulation conditions (wattage, coagulation time, dissociation time, etc.).
[0027]
On the other hand, the sub-operation panel section 12 has two output connectors 40 and 41 capable of outputting microwaves, a simultaneous energizing switch 38 for energizing these output connectors 40 and 41 simultaneously, and a microwave operating electrode 5. A URS switch 39 for turning on the output connectors 40 and 41 when a load is applied, a foot switch connector 42, and a main power switch 43 are provided.
[0028]
In this case, microwave operation electrodes 5 and 5 are connected to the output connectors 40 and 41 via high-frequency coaxial cables 4 and 4, respectively. Then, microwaves are output from the microwave operation electrodes 5 and 5.
In the present embodiment, the noise filter 3 is provided between the output connector 40 (or 41) and the high-frequency coaxial cable 4.
The foot switch 9 is connected to the foot switch connector 42 via the foot cable 8 described above.
[0029]
As shown in FIG. 3B, a volume control knob 45, a fuse holder 46, a ventilation hole 47, and an equipotential terminal 48 are provided on the rear side of the surgical apparatus main body 2. Handles 44 are provided on both sides of the surgical apparatus main body 2, respectively.
[0030]
2-2 Internal configuration of microwave surgery device
Next, the internal configuration of the microwave operation apparatus according to the present embodiment will be described with reference to the block diagram shown in FIG. The same parts as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.
As shown in FIG. 4, the commercial AC voltage (rated voltage) from the commercial AC power supply is supplied to the set output stabilizing device 53 via the fuse 51, the main power switch 43, and the earth leakage breaker 52. The earth leakage warning light 21a for notifying the earth leakage is attached to the earth leakage breaker 52. The ground warning lamp 21a is provided as the alarm lamp 21 in the alarm area 13 shown in FIG.
[0031]
The set output stabilizer 53 sets a voltage level to be supplied to the high-voltage power supply 56 according to the setting of the output setter 54. The output timing of the set output stabilizing device 53 is controlled by the output control device 55. The output display 29 is a display for displaying the set value of the output setting device 54.
[0032]
The high-voltage power supply 56 includes a high-voltage transformer or the like, and boosts the voltage from the set output stabilizing device 53 and outputs the boosted voltage to the microwave oscillator 57.
The microwave oscillator 57 is configured by a magnetron, and generates a microwave of, for example, 2450 MHz using a boosted voltage from the high-voltage power supply 56. The output circuit is provided with an electric insulator so as to cut off direct current.
[0033]
The microwave generated by the microwave oscillator 57 is supplied to the microwave operation electrode 5 through the noise filter 3 and the coaxial relay 59 of the microwave transmission unit 58 surrounded by the broken line, and the high-frequency coaxial cable 4 to perform the microwave operation. The subject 7 is irradiated from the electrode 5 for use.
[0034]
The contact checker 61 detects whether or not the microwave surgical electrode 5 is in contact with the subject 7 in order to prevent the microwave from being output from the microwave surgical electrode 5 by mistake. The detection result is output to the output control device 55.
[0035]
The output control device 55 controls the voltage of the predetermined level from the set output stabilizer 53 to be input to the high voltage power supply 56 for the time set by the output time setting device 63 when the foot switch 9a is operated. I have. The output control device 55 performs output control based on the detection result of the contact checker 61 described above. The operating voltage of the output control device 55 is supplied from the low-voltage power supply circuit 62.
[0036]
The magnetron forced cooling device 64 forcibly cools the magnetron of the microwave oscillator 57. The magnetron forced cooling device 64 is provided with a cooling fan monitoring lamp 21b for monitoring the state of the cooling fan and notifying when an abnormality occurs in the cooling fan.
[0037]
The low-voltage power supply circuit 62 converts the commercial voltage input via the earth leakage breaker 52 to a predetermined low-voltage level and outputs it. The output voltage is supplied to the output control device 55, the foot switch 9a, the audio output device 65, and the like as drive power.
[0038]
The sound output device 65 outputs an alarm sound from the speaker 66 when an abnormality is detected when the output control device 55 outputs microwaves, or when an abnormality is detected in the ground detection circuit 67 or the tissue dissociation device 69.
The audio output device 65 outputs an alarm sound from the speaker 66 when the earth current detection circuit 67 detects a leakage current.
[0039]
Further, in the microwave surgical apparatus 1 of the present embodiment, after the microwave surgical electrode 5 is inserted into the tissue for surgery and the surgery is performed, when the microwave surgical electrode 5 is pulled out from the tissue. A tissue dissociation device 69 is provided to prevent the tissue from adhering to the microwave surgical electrode 5.
[0040]
The tissue dissociation device 69 supplies a cathode DC current of about several mA to the microwave surgical electrode 5 via the coaxial relay 59 after the operation, so that the tissue can be separated from the microwave surgical electrode 5. Moisture condensed around the central electrode, which becomes negative due to the electroosmosis phenomenon with the cell membrane as a boundary, prevents the tissue from adhering to the microwave surgical electrode 5.
The energization time of the tissue dissociation device 69 can be set by an energization time setting unit 70, and the energization time is usually set to a short time (for example, about 60 seconds).
The tissue dissociation device 69 is turned on / off by operating, for example, the foot switch 9b to turn on / off the DC power supply 68.
[0041]
2-3 Structure of Microwave Surgery Electrode
Here, an example of the structure of the electrode for microwave operation will be described with reference to FIG.
FIG. 5A is an overall structural view of the surgical electrode, and FIG. 5B is an enlarged view of a distal end portion of the surgical electrode.
The microwave surgical electrode 5 shown in FIGS. 5A and 5B is a surgical electrode formed of, for example, an MRI-compatible nonmagnetic material.
In such a microwave surgical electrode 5, a substantially cylindrical external electrode 72 is attached to a connector main body 71. A center electrode 74 is attached to the tip of the external electrode 72 via an insulator 73.
The center electrode 74 is connected to a center electrode (not shown) in the connector body 71 via a center conductor 75 formed in the insulator 73 and a center conductor (not shown) in the external electrode 72. The external electrode 72 is connected to an external electrode of the connector main body 71. Note that the external electrode 72 and the center electrode are insulated.
[0042]
3. Background of the Invention
By the way, as described above, when the operation is performed by the microwave operation apparatus 1 while simultaneously displaying the MR images by the microwave operation apparatus 1 and the MRI apparatus 6, the operation for the MRI-compatible operation as described above is performed. The mere use of the instrument still causes a problem of disturbance of the MR image obtained by the MRI apparatus.
[0043]
The present inventors have pursued the cause of this problem, and as a result, have clarified the following.
The MRI apparatus 6 generates a weak electromagnetic wave (RF) having the same frequency as the resonance frequency of protons in the living body (for example, 21.28 MHz in the case of an MRI apparatus having a static magnetic field strength of 0.5 T (Tesla: Tesla)). A transmitting device (not shown) for sending the protons as the imaging frequency to the protons, and a receiving device (not shown) for receiving electromagnetic waves of the same frequency re-radiated from the protons when the transmission is stopped are provided.
[0044]
On the other hand, the magnetron that generates microwaves in the microwave surgical apparatus 1 is widely used in microwave ovens and the like because of its high efficiency and large output and stable operation, but the oscillation waveform of the magnetron is low. Continuity noise is generated by superimposing a specific noise waveform at a level.
For this reason, when the MRI apparatus 6 and the microwave operating apparatus 1 are used together, an electromagnetic wave having the same frequency as the resonance frequency of the proton is generated from the continuity noise superimposed on the oscillation waveform of the magnetron. It was found that a correct MR image could not be obtained because the signal resonated into the receiving device and mixed with and interfered with the received signal re-emitted from the proton.
[0045]
Therefore, when an electromagnetic wave (a noise component that resonates with the frequency for MR imaging) that is the same as the resonance frequency of the biological proton appears in the continuity noise of the magnetron, the noise component is guided to the external ground by the noise filter 3 and removed. Then, the MRI apparatus 6 can display a high-resolution image or a temperature distribution image of a diseased tissue site irradiated with microwaves from the microwave operating apparatus 1 without affecting the MR image. It turned out to be.
[0046]
In general, in the MRI apparatus 6, when the MR signal is processed in the MRI apparatus main body 6a and the MR image of the subject 7 is displayed on the monitor 6d, the distance between the imaging frequency f of the MRI apparatus 6 and the magnetic field strength T of the static magnetic field is measured. Has the following relationship:
1.0T = 42.56MHz
0.5T = 21.28MHz
0.3T = 12.768 MHz
0.2T = 8.512MHz
[0047]
This is because, for example, when the magnetic field strength T of the MRI apparatus 6 is 1.0 T, continuity noise in a band around 42.56 MHz generated in the microwave oscillator 57 of the microwave surgical apparatus 1 is generated by the microwave surgical electrode 5. Means that the MR image of the MRI apparatus is disturbed.
[0048]
Therefore, in the microwave operating apparatus 1 of the present embodiment, the noise filter 3 is provided between the microwave oscillator 57 and the microwave operating electrode 5 so that the required band which affects the MR image generated by the magnetron is continuously connected. Sex noise is removed.
[0049]
In addition, as described above, in the device disclosed in Patent Document 1, if another treatment device or a living body monitoring device is used in combination, the ground circuit of any device may be When an abnormality occurs, the surgeon or the patient may give an electric shock due to a leakage current.
For this reason, in the microwave surgical apparatus 1 of the present embodiment, in order to prevent electric shock due to leakage current to the patient and the operator, although not shown, the output circuit of the microwave oscillator 57 is made of silicon rubber which cuts off direct current. An insulator is provided. As a result, the microwave oscillator 57 floats from the ground of the microwave operating apparatus 1.
[0050]
That is, in a general noise filter including a coaxial filter as described in Patent Document 1, an unnecessary signal is obtained from a microwave signal component having a good ground and transmitted using an inner conductor having a coaxial structure. While the components are removed, the microwave surgical apparatus 1 according to the present embodiment, as described above, connects the outer skin portion of the high-frequency coaxial cable 4, that is, the outer conductor portion, to the ground in a DC manner. I try not to. However, in that case, an unnecessary high-frequency signal transmitted to the external electrode 72 of the microwave surgical electrode 5 via the external conductor of the high-frequency coaxial cable 4 cannot be removed.
[0051]
Therefore, in the present embodiment, the noise filter 3 is formed as follows in order to remove the noise component generated in the magnetron and affecting the MR image after being formed so as to float from the ground. .
[0052]
4. Configuration of noise filter
4-1 Structure of noise filter
Hereinafter, the structure of the noise filter provided in the microwave operating apparatus according to the present embodiment will be described.
In the present embodiment, the noise filter 3 that can be externally attached to the surgical apparatus main body 2 will be described as an example. However, the noise filter can be provided inside the surgical apparatus main body 2 as a matter of course. Further, the noise filter 3 can be provided between the high-frequency coaxial cable 4 and the microwave operation electrode 5.
The noise filter 3 described in the present embodiment can be externally attached to the surgical operation apparatus main body 2, so that its appearance is covered by a shield case 81 as shown in FIG. The shield case 81 and the connector 82 are insulated by an insulating member such as a glass epoxy resin.
[0053]
The circuit configuration of the noise filter 3 includes a connector 82 connected to the output connectors 40 and 41 of the surgical apparatus main body 2 and a connector 83 connected to the connector main body 71 of the microwave surgical electrode 5. Between them, an internal transmission line 84 corresponding to the internal conductor and an external transmission line 85 corresponding to the external conductor are formed.
As illustrated, capacitors C1 and C2 are connected to the transmission lines 84 and 85, respectively, as a first band-pass circuit formed to be able to pass microwave signals.
Between the internal transmission line 84 between the connector 82 and the capacitor C1 and the shield case 81, a tuning circuit formed by connecting the coil L1 and the capacitor C3 in series is provided as a second bandpass circuit. .
A tuning circuit formed by connecting a coil L2 and a capacitor C4 in series is also provided as a second band-pass circuit between the external transmission path 85 between the connector 82 and the capacitor C2 and the shield case 81. ing.
Further, between the external transmission line 85 and the shield case 81, correction capacitors C5 and C6 for correcting the mechanically generated capacitance and the like of the noise filter 3 when configuring the noise filter 3 are connected. I have to.
[0054]
Therefore, if such a noise filter 3 is provided between the surgical device main body 2 of the microwave surgical device 1 and the microwave operating electrode 5, the noise filter 3 is supplied from the surgical device main body 2 via the connector 82. Among the high-frequency signals, the microwave signal necessary for the operation has a high frequency, and therefore can be supplied from the connector 83 to the microwave operation electrode 5 through the capacitors C1 and C2.
[0055]
On the other hand, a high-frequency signal (hereinafter, referred to as a “noise component signal”) that interferes with an MRI image cannot pass through the capacitors C1 and C2 because of a low frequency, and a series circuit of a coil L1 and a capacitor C3. Then, the current is led from the screw terminal 86 of the shield case 81 to the ground via a series circuit of the coil L2 and the capacitor C4. Thereby, the ratio of the noise component signal equivalent to the frequency for MR imaging supplied to the microwave surgical electrode 5 can be significantly reduced.
[0056]
As described above, in the microwave surgical apparatus 1 according to the present embodiment, the noise filter 3 that removes only the noise component that resonates with the frequency for MR imaging from the continuous noise generated by the magnetron to the external ground is provided. Therefore, even when the operation is performed by combining the microwave operation apparatus 1 and the MRI apparatus 6, it is possible to remove and reduce an obstacle to the MR image of the MRI apparatus 6.
[0057]
4-2 Filter characteristics
8 to 10 show examples of the filter characteristics of the above-described noise filter.
Here, a filter characteristic of a noise filter for enabling the microwave surgical apparatus 1 of the present embodiment to be used simultaneously with the MRI apparatus 6 having a magnetic field strength of 0.5 T will be described as an example.
FIG. 8 is a diagram illustrating filter characteristics in the entire band of the noise filter 3.
FIG. 8A shows the insertion loss characteristics of the noise filter 3 according to the present embodiment in the entire band (0 to 3000 MHz). The return loss in the entire band of the noise filter 3 is shown as in FIG.
Also, the insertion loss characteristics of the noise filter 3 in the stop band (21.28 MHz ± 100 kHz) are shown as in FIG. 9A, and the return loss is as shown in FIG. 9B.
Further, the insertion loss characteristic in the pass band (2200 MHz to 2500 MHz) of the noise filter 3 is shown as in FIG. 10A, and the return loss is shown as in FIG. 10B.
[0058]
From these characteristic data shown in FIGS. 8 to 10, the noise filter 3 shows that the frequency component around 21.28 MHz that causes an obstacle to the MRI image in the MRI apparatus 6 with the magnetic field strength of 0.5 T is attenuated by 50 dB or more. I understand. In addition, it can be seen that the frequency components of 2300 MHz to 2500 MHz required in the microwave operation apparatus are transmitted with a slight loss of about 0.4 dB.
[0059]
That is, the noise filter 3 can sufficiently attenuate only the frequency component near 21.28 MHz that impairs the MRI image, while hardly attenuating the frequency component of 2300 MHz to 2500 MHz necessary for the operation. Can be formed.
[0060]
FIG. 11 is a diagram showing a state of an MR image when the microwave operation apparatus 1 and the MRI apparatus according to the present embodiment are operated at the same time.
An MR image when the microwave operation apparatus 1 and the MRI apparatus of the present embodiment are operated at the same time is shown as in FIG. FIG. 11B shows an MR image obtained when the conventional microwave operation apparatus and the MRI apparatus are simultaneously operated, that is, an MR image obtained when the microwave operation apparatus having no noise filter and the MRI apparatus are simultaneously operated. Is shown as Therefore, as can be seen by comparing FIGS. 11A and 11B, if the noise filter 3 is provided as in the microwave surgical apparatus 1 according to the present embodiment, it is possible to prevent noise in the MR image. Proven.
[0061]
As a result, microsurgery can be performed while displaying a higher-resolution real-time image than a nuclear magnetic resonance imaging apparatus. Therefore, while observing the temperature distribution at the lesion tissue site during the microwave irradiation, it is possible to confirm the therapeutic effect such as the coagulation change and the coagulation range of the living tissue.
[0062]
In the present embodiment, the noise filter 3 when the imaging frequency f of the MRI apparatus 6 is 21.28 MHz, that is, when the static magnetic field strength is 0.5 T has been described as an example, but this is merely an example. For example, even when the imaging frequency f of the MRI apparatus 6 is 42.56 MHz, 12.768 MHz, 8.512 MHz, etc., the imaging frequency of the MRI image is hardly attenuated for the frequency components of 2300 MHz to 2500 MHz necessary for the operation. By forming the noise filter 3 that can sufficiently attenuate only the frequency components near f, it is needless to say that the noise of the MR image can be prevented even when the microwave surgical apparatus 1 and the MRI apparatus are used simultaneously. Nor.
[0063]
【The invention's effect】
As described above, according to the microwave surgical apparatus of the present invention, the noise filter means is provided between the microwave oscillating means and the surgical electrode, and the continuous wave included in the microwave signal output from the microwave oscillating means is provided. Since only the noise component that resonates with the imaging frequency of the tomographic image is guided to the external ground and removed from the directional noise, microwaves that do not affect the MR image even when a high magnetic field MRI apparatus is used A surgical device can be realized.
This makes it possible to display a high-resolution image or a temperature distribution image of a diseased tissue site in real time by an MRI apparatus, so that it is possible to easily confirm a therapeutic effect such as a coagulation change or a coagulation range of a living tissue. it can.
[0064]
In addition, an electric insulator that blocks direct current is provided in the output circuit of the microwave oscillating means, and a tuning circuit is formed by a capacitor and an inductor between the transmission line of the noise filter means and the external ground, so that the noise filter means In general, if the microwave operation device is used in combination with another treatment device or a living body monitoring device, the grounding circuit of any of these devices may become abnormal due to some cause when floating. However, it is possible to configure so that the surgeon and the patient do not receive the electric shock due to the leakage current.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a surgery system using a microwave surgery apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing an external configuration of a microwave surgical apparatus according to the present embodiment.
FIG. 3 is a diagram showing an external configuration of a microwave operation apparatus according to the present embodiment.
FIG. 4 is a block diagram showing an internal configuration of the microwave operation apparatus according to the present embodiment.
FIG. 5 is a diagram showing a structural example of a microwave surgical electrode.
FIG. 6 is a diagram showing an external structure of a noise filter.
FIG. 7 is a diagram showing a circuit configuration of a noise filter.
FIG. 8 is a diagram illustrating characteristics of a noise filter.
FIG. 9 is a diagram showing characteristics of a noise filter.
FIG. 10 is a diagram illustrating characteristics of a noise filter.
FIG. 11 is a diagram showing a state of an MR image.
[Explanation of symbols]
Reference Signs List 1 microwave surgical device, 2 surgical device main body, 3 noise filter, 4 high-frequency coaxial cable, 5 microwave surgical electrode, 6 MRI device, 7 patient, 8 foot cable, 9 foot switch, 10 stand, 11 main operation panel , 12 sub-operation panel section, 13 alarm area, 14 mode area, 15 coagulation area, 16 dissociation area, 17 memory area, 21 lamps, 22 mode changeover switch, 23 repeat number display section, 24 25 microwave output setting switch, 26 27 changeover switch, 28 coagulation confirmation lamp, 29 output display, 30 coagulation time display, 31 coagulation time unit confirmation lamp, 32 dissociation confirmation lamp, 33 dissociation time display, 34 dissociation time setting switch, 35 dissociation current display, 36 Dissociation current setting switch, 37 Memory switch, 38 Simultaneous energizing switch , 39 switch, 40 41 output connector, 42 foot switch connection connector, 43 main power switch, 44 handle, 45 volume control knob, 46 fuse holder, 47 ventilation hole, 48 equipotential terminal, 51 fuse, 52 earth leakage breaker, 53 Setting output stabilizer, 54 output setting device, 55 output control device, 56 high voltage power supply, 57 microwave oscillator, 58 microwave transmission section, 59 coaxial relay, 61 contact checker, 62 low voltage power supply circuit, 63 output time setting device, 64 Magnetron forced cooling device, 65 sound output device, 66 speaker, 67 ground detection circuit, 69 tissue dissociation device, 71 connector body, 72 external electrode, 73 insulator, 74 center electrode, 75 center conductor, 81 shield case, 82 83 connector , 84 internal transmission line, 85 external transmission line 86 screw terminals

Claims (5)

A microwave surgical apparatus that can be used under a state where imaging of a tomographic image is performed by a nuclear magnetic resonance imaging apparatus,
A microwave oscillating means, which is configured by a magnetron, and provided with an electrical insulator that blocks direct current in an output circuit that oscillates and outputs a microwave signal of a predetermined frequency;
A surgical electrode configured to be able to irradiate the microwave signal to a diseased tissue site,
A noise component that is provided between the microwave oscillating means and the surgical electrode and resonates with the imaging frequency of the tomographic image from continuity noise included in the microwave signal output from the microwave oscillating means Noise filter means for guiding the noise to an external ground for removal,
A microwave surgical device comprising: The noise filter means includes:
By removing a noise component affecting the tomographic image taken by the nuclear magnetic resonance imaging apparatus, the nuclear magnetic resonance imaging apparatus can display the temperature distribution of the lesion tissue site in real time. The microwave surgical device according to claim 1, wherein 2. The microwave surgical apparatus according to claim 1, wherein the noise component removed by the noise filter means is determined by a magnetic field intensity of the nuclear magnetic resonance imaging apparatus. The noise filter means includes:
A first band-pass circuit which is inserted into each of a pair of transmission paths for transmitting the microwave signal from the microwave oscillation means to the surgical electrode, and is formed so as to pass at least a microwave signal of a predetermined frequency; When,
A second component that is inserted between the transmission line and the external ground and that is formed so as to be able to pass only a noise component having a frequency that resonates with the imaging frequency of the tomographic image, out of continuity noise generated in the magnetron; A bandpass circuit;
The microwave surgical device according to claim 1, comprising: 5. The micro-cell according to claim 4, wherein the first band-pass circuit is formed by a capacitor, and the second band-pass circuit is formed by a tuning circuit formed by connecting a capacitor and an inductor in series. Wave surgery device.

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